Holding sleeve for a rock drill



5, 1963 MASAHISA TERAO 3,100,118

HOLDING SLEEVE FOR A ROCK DRILL Filed May 22, 1961 United States Patent 3,100,118 HOLDING SLEEVE FOR A ROCK DRILL Masahisa Terao, 36 Z-chome, Magaike-cho, Showalru, Nagoya, Japan Filed May 22, 1961, Ser. No. 111,825 2 Claims. (Cl. 279103) This invention relates to a holding sleeve for a rock drill into which the drill bar will accurately fit and be seated, whereby the end of the drill bar which fits into the pneumatic drill or hammer is fitted to the shape of a seat, and the usual collar on this same end of the drill bar is eliminated.

An object of my invention is to provide a means of mounting a drill bar in the pneumatic drill or hammer by means of a separate sleeve which is fitted into the pneumatic drill or hammer. The drill bar itself may be accurately machined or forged to fit into the sleeve, and also the sleeve accurately fits into the pneumatic drill or hammer, thus eliminating vibration due to misalignment of parts.

Another object of my invention is to provide a holding sleeve for a rock drill in which the drill bar is formed with a tapered end which accurately fi-ts into a seat, and Where the holding flange is eliminated from the drill bar, thus eliminating a source of failure due to forging or otherwise forming the flange on the drill bar.

Another object of my invention is to provide a holding sleeve for a rock drill in which the drill bar is slidably fitted into a seat, so that the drill bar may be readily removed or replaced from time to time as necessary.

Other objects, advantages and features of invention may appear from the accompanying drawing, the subjoined detailed description and the appended claims.

In the drawing:

FIGURE 1 is a fragmentary side elevation of the sleeve and a fragment of the drill bar inserted therein.

FIGURE 2 is a bottom plan view of the sleeve.

FIGURE 3 is a longitudinal sectional view of the sleeve and drill bar.

FIGURE 4 is a side elevation with parts broken away to show interior construction of the sleeve.

Referring more particularly to the drawing, the numeral 1 indicates the drill stock of the usual pneumatic drill or hammer. A spring latch 2, also of usual and well known construction, is mounted 'on the stock 1 and engages the sleeve to hold that sleeve in the stock 1, as will be subsequently described. The stock 1 is formed with an elongated opening 3 which is polygonal in cross section to receive a driving sleeve, as will be subsequently described. This polygonal recess or seat in the stock 1 is usual and well known and is incorporated in all usual pneumatic drills or hammers. A sleeve 4 is formed of a suitable metal and is provided with a plurality of external angular faces 5' which accurately fit the angular opening 3 in the stock of the pneumatic drill or hammer. The sleeve 4 has a sliding fit within the opening 3 and, therefore, can be readily inserted or removed when necessary. The angular faces 5 impart a polyhedral form to the outer surface of the sleeve 4 and this form is usually hexagonal, although other shapes may be used. A flange 6 is integrally formed on the lower end of the sleeve 4 and this flange butts against the lower face of the stock 1, as shown in FIGURE 1, and the entire seat is held in position Within the stock by means of the spring latch 2. Thus it will be evident that the sleeve 4 is detachably held in the stock 1 and is nonrotatably held in that stock. The drill bar 7, also formed of a suitable metal, has the upper end thereof tapered as shown at 8. The tapered tip 8 is uniform throughout its length, and the angle of taper is such that it will accurately fit a seat 9 in the sleeve 4 and will be held within the sleeve 4 by frictional engagement. A properly tapered angle of the tip 8 will insure that the drill bar 7 is held within the sleeve 4, and for the additional reason that the impact of the pneumatic drill or hammer is downward against the drill bar 7. If it is desired to provide water circulation through the drill bar, I may also include a hole 10 in the upper end of the sleeve 4, which hole extends into the seat area 9 of the sleeve. The drill bar 7 is then also provided with a longitudinal bore 11 which extends the length of the drill bar, and permits fluid to pass to the lower end of the drill bar during the drilling or cutting operation. The tip 8 is circular in cross section so that it will fit into the seat 9.

Having described my invention, I claim:

1. A holding sleeve for a rock drill and hammer, said holding sleeve being relatively short in length and extending into the stock of a drill for about its entire length, flat external faces on said sleeve adapted to fit a flat faced recess in the stock of a drill, said sleeve having an inner tapered seat formed therein, said seat extending from one end of the sleeve and partly through said sleeve, a drill bar, a tapered tip on one end of said drill bar, said tapered tip fitting into said tapered seat and resting thereon in the assembled position of the parts.

2. A holding sleeve for a rock drill and hammer, said holding sleeve being relatively short in length and extending into the stock of a drill for about its entire length, flat external faces on said sleeve adapted to lit a flat faced recess in the stock of a drill, a flange formed on one end of said sleeve, said flange being positioned on the outside of the stock of the drill in the assembled position of the parts, said flange being engageable by latch means on the rock drill to hold said sleeve in the rock drill, said sleeve having an inner tapered seat formed therein, said seat extending from one end of the sleeve and partly through said sleeve, a drill bar, a tapered tip on one end of said drill bar, said tapered tip fitting into said tapered seat and resting thereon in the assembled position of the pants.

References Cited in the file of this patent UNITED STATES PATENTS 1,884,650 Gartin Oct. 25, 1932 1,984,220 Lang Dec. 11, 1934 2,028,993 Pollard Jan. 28, 1936 2,440,150 Mitchell Apr. 20, 1948 FOREIGN PATENTS 99,133 Sweden June 11, 1940 

1. A HOLDING SLEEVE FOR A ROCK DRILL AND HAMMER, SAID HOLDING SLEEVE BEING RELATIVELY SHORT IN LENGTH AND EXTENDING INTO THE STOCK OF A DRILL FOR ABOUT ITS ENTIRE LENGTH, FLAT EXTERNAL FACES ON SAID SLEEVE ADAPTED TO FIT A FLAT FACED RECESS IN THE STOCK OF A DRILL, SAID SLEEVE HAVING AN INNER TAPERED SEAT FORMED THEREIN, SAID SEAT EXTENDING FROM ONE END OF THE SLEEVE AND PARTLY THROUGH SAID SLEEVE, A DRILL BAR, A TAPERED TIP ON ONE END OF SAID DRILL BAR, SAID TAPERED 